Drug binding is very important for the effectiveness of a drug. Plasma protein binding and tissue binding are two ways of drug binding. Identifying the difference between plasma protein binding and tissue binding in pharmacology can pose challenges for researchers and clinicians alike. Clearing up the confusion between these concepts is important for effective drug therapy and avoiding adverse effects.
The key difference between plasma protein binding and tissue binding is the nature of binding. Plasma protein binding defines the degree of binding of a drug to plasma proteins, while tissue binding defines the degree of binding of a drug to one or more of the several tissue components.
CONTENTS
1. Overview and Key Difference
2. What is Plasma Protein Binding
3. What is Tissue Binding
4. Similarities – Plasma Protein Binding and Tissue Binding
5. Plasma Protein Binding vs Tissue Binding in Tabular Form
6. Summary – Plasma Protein Binding vs Tissue Binding
7. FAQ – Plasma Protein Binding and Tissue Binding
What is Plasma Protein Binding?
Plasma protein binding refers to the degree to which drugs are attached to blood proteins within the blood plasma. The efficacy of the drug may vary based on which it binds to. When fewer drugs bind to the blood protein, they diffuse through the cell membrane more efficiently. Human serum albumin, lipoprotein, glycoprotein, and α, β‚ and γ globulins are some of the blood proteins that bind to drugs.
Plasma protein binding is weak and thus reversible. Plasma protein binding does not result in toxicity. Furthermore, displacement of drugs from plasma proteins can also be achieved by using other drugs.
What is Tissue Binding?
Tissue binding defines the degree of binding of a drug to one or more of the several tissue components. The body tissues comprise 40% of body weight; hence, tissue-drug binding is much more significant than initially thought. Drugs can bind to extravascular tissues such as the liver, lungs, kidneys, skin, eyes, hair, bones, fats, and nucleic acids. Tissue binding involves strong covalent bonds, making binding irreversible. Furthermore, toxicity is also common in tissue binding. Displacement using other drugs generally does not occur in this case.
Similarities Between Plasma Protein Binding and Tissue Binding
- Plasma protein binding and tissue binding are two ways of drug binding.
- Both binding involve chemical binding.
- They reduce the drug’s efficacy.
- Both are very important for pharmacokinetics.
Comparing the Difference Between Plasma Protein Binding and Tissue Binding
Definition
- Plasma protein binding refers to the degree to which drugs attach to blood proteins within the blood plasma.
- Tissue binding defines the degree of binding of a drug to one or more of the several tissue components.
Examples of Which Drugs Bind
- Blood proteins that bind to drugs are human serum albumin, lipoprotein, glycoprotein, and α, β‚ and γ globulins.
- Extravascular tissues include the liver, lungs, kidneys, skin, eyes, hairs, bones, fats, and nucleic acids.
Bonding Involves
- Plasma protein binding can occur through weak bonds.
- Tissue binding can occur through strong bonds.
Irreversibility and Reversibility of the Bonds
- Plasma protein binding is often reversible.
- Tissue binding is irreversible.
Toxicity
- Plasma protein binding typically does not result in toxicity.
- Tissue binding can sometimes lead to toxicity.
The infographic below presents the differences between plasma protein binding and tissue binding in tabular form for side-by-side comparison.
Summary – Plasma Protein Binding vs Tissue Binding
Drug distribution and binding are very important when it comes to the efficacy of drug activity. Plasma protein binding and tissue binding are two ways of drug binding. Both bindings reduce the drug’s efficacy. However, plasma protein binding refers to the degree of binding of a drug to plasma proteins, while tissue binding refers to the degree of binding of a drug to one or more of the several tissue components. Thus, this summarizes the difference between plasma protein binding and tissue binding.
FAQ: Plasma Protein Binding and Tissue Binding
1. What is tissue and protein binding?
- The tissue binding of drugs and plasma protein binding significantly impact the drug’s pharmacokinetics and pharmacodynamics as it affects both the distribution and elimination processes of the drug. In addition, it also affects the pharmacological effect of the drug.
2. What are the two types of protein binding?
- Protein + drug ⇌Protein-drug complex is the interaction that is formed in protein binding. Protein binding may be divided into intracellular binding and extracellular binding.
3. What are the methods of determining plasma and tissue binding of drugs?
- Protein binding can be assayed by different methods, such as equilibrium dialysis, ultrafiltration, ultracentrifugation, gel filtration, binding to albumin microspheres, circular dichroism, and other tissue binding techniques.
4. What is the meaning of tissue binding of drugs?
- Tissue binding defines the degree of binding of a drug to one or more of the several tissue components. Moreover, for a drug that is highly tissue-bound, very little drug remains in circulation; thus, plasma concentration is low, and the volume of distribution is high.
5. What are the extravascular tissues drugs bind to?
- Drugs have the potential to bind to a wide array of extravascular tissues throughout the body. These include vital organs such as the liver, lungs, and kidneys, as well as external tissues like the skin and eyes. Furthermore, drugs can interact with structural components such as hairs and bones, as well as adipose tissue (fats) and nucleic acids within cells.
Reference:
1. “Plasma Protein Binding.” REVIVE.
2. “Tissue Binding of Drugs (Tissue Localization of Drugs) – Protein Binding of Drugs.” Pharmacy180.Com.
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1. “Choice of Tablets” (CC0) via Pexels